docs: Move the GUnixCredentialsMessage SECTION

Move it to the struct docs.

Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>

Helps: #3037

gio/gunixcredentialsmessage.c

@@ -16,31 +16,29 @@
  */
 
 /**
- * SECTION:gunixcredentialsmessage
- * @title: GUnixCredentialsMessage
- * @short_description: A GSocketControlMessage containing credentials
- * @include: gio/gunixcredentialsmessage.h
- * @see_also: #GUnixConnection, #GSocketControlMessage
+ * GUnixCredentialsMessage:
  *
- * This #GSocketControlMessage contains a #GCredentials instance.  It
- * may be sent using g_socket_send_message() and received using
- * g_socket_receive_message() over UNIX sockets (ie: sockets in the
- * %G_SOCKET_FAMILY_UNIX family).
+ * This [class@Gio.SocketControlMessage] contains a [class@Gio.Credentials]
+ * instance.  It may be sent using [method@Gio.Socket.send_message] and received
+ * using [method@Gio.Socket.receive_message] over UNIX sockets (ie: sockets in
+ * the `G_SOCKET_FAMILY_UNIX` family).
  *
  * For an easier way to send and receive credentials over
  * stream-oriented UNIX sockets, see
- * g_unix_connection_send_credentials() and
- * g_unix_connection_receive_credentials(). To receive credentials of
+ * [method@Gio.UnixConnection.send_credentials] and
+ * [method@Gio.UnixConnection.receive_credentials]. To receive credentials of
  * a foreign process connected to a socket, use
- * g_socket_get_credentials().
+ * [method@Gio.Socket.get_credentials].
  *
- * Since GLib 2.72, #GUnixCredentialMessage is available on all platforms. It
+ * Since GLib 2.72, `GUnixCredentialMessage` is available on all platforms. It
  * requires underlying system support (such as Windows 10 with `AF_UNIX`) at run
  * time.
  *
  * Before GLib 2.72, `<gio/gunixcredentialsmessage.h>` belonged to the UNIX-specific
  * GIO interfaces, thus you had to use the `gio-unix-2.0.pc` pkg-config file
  * when using it. This is no longer necessary since GLib 2.72.
+ *
+ * Since: 2.26
  */
 
 #include "config.h"

gio/gunixcredentialsmessage.h

@@ -58,14 +58,6 @@ struct _GUnixCredentialsMessageClass
   void (*_g_reserved2) (void);
 };
 
-/**
- * GUnixCredentialsMessage:
- *
- * The #GUnixCredentialsMessage structure contains only private data
- * and should only be accessed using the provided API.
- *
- * Since: 2.26
- */
 struct _GUnixCredentialsMessage
 {
   GSocketControlMessage parent_instance;